This invention relates to a fluid, two-component washing agent of which one component is a cold-stable aqueous dispersion of substantially unsaturated fatty acids, and the other component is a cold-stable aqueous alkaline dispersion.
Two-component washing agents are preparations consisting of two separately prepared and stored washing agent components that are combined only immediately before or at the beginning of the wash process. The present invention concerns such an agent where both components are liquid concentrates which are stable at low temperatures and where one component is in the form of a liquid concentrate containing fatty acids, soaps of fatty acids, as well as other additional surface-active compounds or tensides, and the other component contains the alkali needed for the formation of soap, and other wash alkalies and builder salts.
A wash process with the use of a two-component washing agent is known from British Pat. No. 338,121. The first component consists of soap-producing fatty acids, such as palmitic acid, stearic acid or oleic acid that are present and mixed with emulsifying agents or solvents, such as sulfated olive oil, hydrocarbons, terpentine and chlorohydrocarbons. The second component contains the alkalies required for the formation of soap such as alkali metal hydroxide, carbonates, bicarbonates, and silicates, and is combined with the first component only in the washing solution. Bleaching components may be added in addition. This process has a number of disadvantages that are important especially in highly automated, commercial laundries.
For example, the fatty acids mentioned are difficult to transport and dose automatically by themselves, while the simultaneous use of solvents from the series of hydrocarbons or chlorohydrocarbons poses considerable problems such as increased danger of fire and explosion or toxicological concerns. Besides, the reaction between the fatty acids, which are not present in a sufficiently fine dispersion in the wash liquor, and the alkali proceeds relatively slowly, especially at washing temperatures below 65.degree. C. Furthermore, the reaction is inhibited or partly prevented by the wash, so that fatty acid deposits may be formed on the wash.
Another process known from French Pat. No. 1,460,904 starts with aqueous fatty acid emulsions suitable for the formation of soap, which combine with the wash alkalies in the washing solution. The fatty acid, which is preferably technical grade oleic acid or a low-melting fatty acid mixture (up to a titer of 45.degree. C.), is emulsified in water with a nonionic emulsifier having a low HLB value agent, such as a monolaurate or a monostearate of polyoxyethylene-sorbitan, with the addition of distilled tall oil, if desired. Alkaline substances are not to be added since these break up the emulsions.
It was found that the cleaning power of these preparations is comparatively low since the emulsifying agents employed do not contribute measureably to the washing power. Furthermore, the stability, especially the stability in cold temperatures, of the emulsions is inadequate since de-emulsification occurs below the freezing point, which de-emulsification is not readily reversible after heating.
Liquids of the above-mentioned type, particularly in the form of highly concentrated preparations, continue to be interesting despite these problems. Highly concentrated substances help to keep the costs for packing, transport and storage low. As liquids they possess the added advantage of being readily transportable and dosable. This offers definite advantages for commercial laundries equipped with respective mixing and storage tanks as well as for household washing machines equipped with storing and dosing devices as are being developed at present. The dosing of detergent in these novel machines is specially adjusted for each wash program, which prevents wrong dosing, which is undesirable and places a strain on the waste water. In order to keep pollution of the sewage discharge at a minimum, the phosphate content of the concentrates should be kept low. In addition, the rate of sudsing should be maintained as low as possible without altering the good washing results.